Particle physicists try to understand the nature of nature at the smallest scales possible. Today, we know that atoms do not represent the smallest unit of matter. Particles called quarks and leptons seem to be the fundamental building blocks — but perhaps there is something even smaller. Physicists are still far from understanding why a proton has about 2,000 times more mass than an electron. And on top of it all, scientists suspect a whole new class of undiscovered supersymmetric particles to complete the subatomic family.

Matter at the smallest scale is made of elementary particles, pieces of matter that cannot be divided into anything smaller. As scientists over the past century have looked deeper and deeper into the atom, they have found the smallest things human beings have ever seen. How do they do it?

By using accelerators to smash particles into each other or into targets at high energies, scientists can create different, more massive and more exotic particles. They observe them in particle detectors that are stories high — large and intricate enough to capture details of these particles of matter as they pass through it. To analyze the oceans of data that come through the detectors, physicists develop and make use of computing capabilities with massive amounts of storage and processing power.

The current theoretical framework that describes elementary particles and their forces, known as the Standard Model, is based on experiments that started in 1897 with the discovery of the electron. Today, we know that there are six leptons, six quarks, four force carriers and a Higgs boson. Scientists all over the world predicted the existence of these particles and then carried out the experiments that led to their discoveries. Learn all about the who, what, where and when of the discoveries that led to a better understanding of the foundations of our universe.

To discover what the universe is made of and how it works is the challenge of particle physics. The landmark Quantum Universe report defines the quest of particle physicists to explain the universe in terms of nine key questions. In pursuit of answers to these questions, Fermilab supports researchers, experiments and facilities that promise to revolutionize our understanding of the universe.